Biomedical subjects

R Yamaguchi

Publications and source records attributed to R Yamaguchi.

At least 19 recordsLinked to original sources

PubMed1992

Therapeutic effect of oral dipyridamole on myocardial perfusion and cardiac performance in patients with hypertrophic cardiomyopathy.

Recent studies have indicated that myocardial ischemia could occur and could play an important role in the pathophysiology of patients with hypertrophic cardiomyopathy (HCM). We therefore investigated whether or not dipyridamole--a selective coronary vasodilating agent--could favorably modify myocardial perfusion and the clinical manifestations in 20 patients with HCM (19 nonobstructive and one mildly obstructive) with an average age of 50 years. Oral dipyridamole, 150 mg/day for 2 weeks, prevented reversible perfusion defects initially observed in six patients on baseline exercise thallium-201 (201TI) scintigraphy and significantly increased the 201TI clearance (40 +/- 13% to 44 +/- 12%), while one patient developed new reversible perfusion defects. There were significant increases in echocardiographic fractional shortening and treadmill exercise time and reductions in cardiac size and supraventricular arrhythmias with dipyridamole therapy. These observations suggest that coronary vasodilation with dipyridamole may improve myocardial perfusion and cardiac function in patients with HCM.

Administration, Oral↗

PubMed1992

Highly conserved epitope domain in major core protein p24 is structurally similar among human, simian and feline immunodeficiency viruses.

Linear B cell epitopes were mapped on the major core protein p24 of human immunodeficiency virus type 1 (HIV-1), simian immunodeficiency virus (SIVAGM) and feline immunodeficiency virus (FIV) using a fusion protein-based method and murine monoclonal antibodies reactive against the p24 antigens expressed on the surface of HIV-1- and FIV-infected cells. The results suggest that the sites identified here are encoded at similar positions in the three virus genomes and consist of highly conserved epitopes, which could exhibit immunodominance.

Amino Acid Sequence↗

PubMed1992

Cloning and expression of the gene for the Avi-3 antigen of Mycobacterium avium and mapping of its epitopes.

The Avi-3 antigen, which is found only in Mycobacterium avium culture sonic extracts, is species specific and results in strong skin test activity in guinea pigs sensitized with heat-killed M. avium. Its gene was cloned by using a previously developed single-probe method and was sequenced. The gene encoded a 194-amino-acid polypeptide with a molecular weight of 21,500. A recombinant Avi-3 antigen expressed in Escherichia coli reacted with monoclonal and polyclonal antibodies raised against the native Avi-3 antigen. To identify epitopes on this protein for immunodiagnostic purposes, various parts of the Avi-3 antigen were expressed as beta-galactosidase fusion proteins, using pUR and pURS expression vectors. The clones screened by both antibody reactivity and T-cell proliferative activity defined fragments with coexisting B- and T-cell epitopes. A B-cell epitope (Asn-176 to Ala-186) and two T-cell epitopes (Glu-75 to Ile-86 and Arg-155 to Leu-164) were thus defined. The synthetic polymerized peptides of the T-cell epitopes were proven to elicit a delayed cutaneous hypersensitivity reaction in guinea pigs. This mapping method would be useful in the development of a subunit vaccine consisting of an immunodominant B-cell epitope linked to a T-cell epitope in the vicinity.

Amino Acid Sequence↗

PubMed1991

Incorporation of fatty acids by Streptococcus mutans.

In a series of investigations into the cariogenicity of Streptococcus mutans, we studied the incorporation of exogenous fatty acids with reference to glucosyltransferase secretion and membrane fatty acid changes. When cells were grown with different fatty acids, both saturated and unsaturated fatty acids were readily incorporated into the membrane lipids and were biotransformed and elongated preferentially to the longer 16- and 18-carbon-chain fatty acids. This incorporation and chain-elongation led to significant changes in fatty acids composition. By adding fatty acids to the medium, it was possible to appropriately modify the degree of unsaturation and the relative ratio between specific fatty acids in the membrane lipids of S. mutans.

Fatty Acids↗

PubMed1991

Fusion protein based epitope mapping of the MPB57 protein from Mycobacterium bovis BCG and its epitope insertion into the native protein.

The gene coding for the 12-kDa protein (MPB57) of Mycobacterium bovis BCG has recently been cloned and sequenced (R. Yamaguchi, K. Matsuo, A. Yamazaki, S. Nagai, K. Terasaka, and T. Yamada. 1988. FEBS Lett. 240: 115-117). To map linear B-cell epitopes by beta-galactosidase fusion proteins, we have constructed convenient vectors (pUR278S, pUR288S, and pUR289S) with the SmaI site. Based on recognition by polyclonal antibodies, two epitope regions on the MPB57 protein were identified, both of which corresponded to the amino acid sequences Glu20 to Val45 (26 residues, epitope I region) and Ile78 to Leu86 (9 residues, epitope II). Complementary oligonucleotides encoding epitope II were synthesized, polymerized by a ligase reaction, inserted into the native MPB57 protein gene, and expressed in Escherichia coli, giving rise to epitope-inserted proteins. Their stability and potential uses are described.

Amino Acid Sequence↗

PubMed1991

Eccrine porocarcinoma.

We describe a 78-year-old woman with eccrine porocarcinoma presenting a zosteriform appearance on the lateral upper part of the buttock. Erosion and bleeding were observed in the center of a 50 X 80 mm, erythematous indurated plaque with an elevated border. Posterior to the plaque, there was another erosive plaque, 50 X 20 mm in diameter, with peripheral induration overlaid by two reddish papules. Based on the previous reports of 21 patients with eccrine porocarcinoma in Japan, we discuss the relationship between the clinical pattern and lymph node metastasis. The pedunculated eccrine porocarcinoma has less tendency to metastasize to the regional lymph nodes than the nonpedunculated form.

Adenoma, Sweat Gland↗

PubMed1991

Abnormal structure of the canine oncogene, related to the human c-yes-1 oncogene, in canine mammary tumor tissue.

Cellular oncogenes of genomic DNA in 6 canine primary mammary tumors were screened by Southern blot analysis, using 7 oncogene probes. A canine genomic oncogene related to the human c-yes-1 oncogene was detected as abnormal bands in solid carcinoma genomic DNA digested with EcoRI, HindIII, HindIII-EcoRI, or HindIII-BamHI. Comparison was made between other tumor specimens and control specimens obtained from 4 clinically normal dogs--1 mixed breed and 3 Shiba Inu dogs (the same breed as the dog from which the solid carcinoma was obtained). These abnormal bands were 0.1 to 1 kilobase shorter than the normal gene. However, digestion of genomic DNA obtained from normal WBC of this dog also produced all of the abnormal bands as observed in digested DNA from the solid carcinoma tissue. Therefore, in this dog, the genomic DNA of all somatic cells from the ontogenic stage still had the abnormal sequences related to the human c-yes-1 oncogene, and it is possible that this abnormal structure may have some role (eg, as an initiator) in tumorigenesis or the progression of this tumor.

Animals↗

PubMed1991

[Study on recombinant BCG].

For the purpose to establish the system to express foreign antigen from Mycobacterium bovis BCG. We have cloned, sequenced and expressed genes for secreting proteins, alpha antigen, MPB64, MPB57 and MPB70 from M. bovis BCG. The upstreams and structural genes were characterized. The gene for alpha antigen of Mycobacterium kansasii was also characterized. The gene for alpha antigen of M. kansasii (k-alpha) was chosen for the further study at first. This gene was fused with shuttle plasmid PIJ666-PAL5000 obtained from T. Kisser and transfected to M. bovis BCG (Tokyo). Transformant was obtained by a selection with kanamycin. It was able to secrete k-alpha antigen. DNA-containing a B-cell epitope (Glu-12-Leu-Asp-Arg-Trp-Glu-Lys-Ile-19) of human immunodeficiency virus type 1 P17 gag was fused to this vector at C terminal of k-alpha. Using this vector, we have succeeded to express foreign antigen in M. bovis BCG. The products were analyzed in one or two dimensional electro-phoresis. The results thus obtained will be reported elsewhere.

Amino Acid Sequence↗

PubMed1990

Decreased coronary vasodilatory capacity in hypertrophic cardiomyopathy determined by split-dose thallium-dipyridamole myocardial scintigraphy.

Split-dose thallium-dipyridamole myocardial scintigraphy was performed in patients with nonobstructive hypertrophic cardiomyopathy (HC) who had angiographically normal coronary arteries. The dipyridamole-induced increases in thallium-201 uptake, calculated to evaluate coronary vasodilatory capacity, were significantly lower in 30 patients with HC than in 13 control subjects (177 +/- 58 vs 281 +/- 46%) and the reductions were observed in both the septal and lateral segments. The reductions of the septal segment in HC patients were significantly greater than those in 10 hypertensive patients with comparable degrees of septal hypertrophy. Of patients with HC, 16 had increases in thallium uptake well below the normal range. Compared with those having normal increases, these patients had significantly lower exercise duration (11 vs 15 minutes), with 33% having ST depression develop at a workload less than or equal to 80 watts. These data indicate that approximately one-half of patients with HC have impaired coronary vasodilatory capacity that could be an important pathophysiologic abnormality of HC resulting in the development of myocardial ischemia and the impairment of cardiac performance during exercise.

Adolescent↗

PubMed1990

Establishment of a foreign antigen secretion system in mycobacteria.

In order to develop recombinant Mycobacterium bovis BCG into a useful multivaccine vehicle, we established a foreign antigen secretion system in mycobacteria in which an extracellular alpha antigen of Mycobacterium kansasii was utilized as a carrier. By using this system, a B-cell epitope (Glu-12-Leu-Asp-Arg-Trp-Glu-Lys-Ile-19) of human immunodeficiency virus type 1 p17gag, which was identified by a fusion protein-based method, has been successfully obtained from BCG along with the alpha antigen. This is the first report of expression and secretion of a foreign viral antigen from BCG. It is possible that the system can become a universal vaccination vehicle applicable to protection against various infectious diseases.

Amino Acid Sequence↗

PubMed1990

Cloning and expression of the gene for the cross-reactive alpha antigen of Mycobacterium kansasii.

The gene for the extracellular alpha antigen of Mycobacterium kansasii was cloned by using the alpha-antigen gene fragments of M. bovis BCG as probes. Gene analysis revealed that this gene encodes 325 amino acid residues, including 40 amino acids for the signal peptide, followed by 285 amino acids for the mature protein. A comparison of the nucleotide sequences of the genes isolated from these two mycobacterial species showed that the levels of DNA and amino acid homology were 84.8 and 89.1%, respectively. The hydropathy profiles were also compared, and two highly changed hydrophilic regions were observed, which might account for the antigenic diversity of this antigen or its acquirement of antigenic specificity.

Amino Acid Sequence↗

PubMed1990

Tissue culture of feline normal mammary gland.

To study the growth and morphology of feline mammary epithelial cells in vitro, normal feline mammary tissues as well as cells collected from feline milk were cultured and examined using phase-contrast microscopy and immunohistochemistry. The method employed was a modification of Hiratsuka et al., and was found to be useful for the culture of dissociated feline mammary tissue. Small polygonal cells and large spindle-shaped cells that were positively stained with anti-keratin and anti-actin antibodies formed colonies with a pavement-like structure in culture of mid-pregnant mammary gland. Cultures of involuting mammary gland were composed mainly of small spindle-shaped cells, which were negative for keratin immunostaining and thought to be fibroblasts. Myofibroblasts, which participate in feline mammary carcinogenesis, and show keratin negative, actin positive, were not encountered in the present culture system of normal mammary gland. The cells from milk formed small colonies, but did not grow to reach confluent monolayer.

Animals↗

PubMed1990

Plate and collagen-gel cultures of normal canine mammary epithelial cells.

Plate and collagen gel (floating or embedded) cultures were made to study the cell morphology and growth characteristics of canine mammary epithelial cells in vitro. Hiratsuka's method was satisfactory for the separation of the epithelial cells from the fibroblasts in explants of canine mammary tissue. In the plate culture method, epithelial cells migrated out from the explants to form colonies. The characteristic features of epithelial colonies in this culture system were polygonal cells situated in the centre, elliptical cells in the outer region and large spindle-shaped cells, thought to be myoepithelial cells, at the periphery. These epithelial cells showed a pavement-like appearance and were positive for antikeratin antibody. On floating gels, the cells changed their shape dramatically from flattened to rounded when the gel was released from the glass dish. Cells embedded in collagen gels grew to form duct-like structures.

Animals↗

PubMed1990

An outbreak of congenital hydranencephaly and cerebellar hypoplasia among calves in South Kyushu, Japan: a pathological study.

An outbreak of congenital hydranencephaly and cerebellar hypoplasia occurred between November 1985 and May 1986 in Miyazaki, South Kyushu, Japan. Seventy-three calves had nervous signs of varying severity such as inability to stand, locomotor difficulties, defective vision and difficulty in sucking. At necropsy, 62 calves had macroscopic lesions in the central nervous system: hydranencephaly accompanied by cerebellar hypoplasia in 47; hydranencephaly alone in eight; and dilatation of the lateral ventricle in seven; none had arthrogryposis. Microscopically, all 62 cases involved various degrees of hypoplasia of neural components, such as total or partial thinning of the cerebral or cerebellar laminae. Heterotopia, such as abnormal islands of granule cells or Purkinje cells was also observed. Fourteen of these animals had other lesions such as non-purulent encephalitis, focal gliosis, neuronal degeneration, calcification or pseudocalcification, and cholesterol deposits, activation of vascular endothelial cells and haemorrhage. From the findings, these cases were considered to represent mainly hypoplasia of nerve tissue due to infection with a virus different from Akabane virus.

Animals↗

PubMed1989

Parameters affecting in vitro bond strength of composites to enamel and dentin.

In vitro tensile bond strengths of Photo Clearfil Bright (PB) and Clearfil Photo Posterior (CP) with Clearfil Photo Bond to human enamel and dentin were determined by a truncated cone bond test. Parameters tested were: four substrates (etched enamel; unetched dentin, D1; dentin conditioned with 10% polyacrylic acid, D2; and dentin etched with phosphoric acid, D3); two techniques (bonding agent prepolymerized, and bonding agent and composite polymerized together); and two storage times in 37 degrees C water (one day and one week). Bond strengths of PB and CP to enamel ranged from 15 to 25 MN/m2 and 19 to 24 MN/m2, respectively. Bond strengths of PB to dentin ranged from 10.2 to 13.6 MN/m2 for D1, 8.2 to 10.5 MN/m2 for D2, and 5.5 to 7.8 MN/m2 for D3. Bond strengths of CP to dentin ranged from 7.6 to 12.3 MN/m2 for D1, 6.8 to 9.5 MN/m2 for D2, and 4.6 to 6.7 MN/m2 for D3. Bond strengths were higher to enamel than to dentin. The highest bond strengths to dentin were to unetched dentin, followed by conditioned dentin, and then etched dentin. Polymerization techniques and storage times did not affect the bond strengths.

Composite Resins↗

PubMed1989

Complete nucleotide sequence of immunogenic protein MPB70 from Mycobacterium bovis BCG.

The extracellular protein MPB70 is a heat-stable immunogenic protein which was found in the culture filtrate of Mycobacterium bovis BCG Japanese. We determined the complete nt and aa sequences of MPB70 and correlated with the previously reported data. The N-terminal sequence revealed that the signal peptide (SP) consisted of 30 aa and that the mature protein had 163 aa with a molecular weight of 16,305. The SP displayed a characteristic feature of an Ala-rich property which would be efficient in a SP function.

Amino Acid Sequence↗

PubMed1989

A case of bullous pemphigoid induced by tiobutarit (D-penicillamine analogue).

A 61-year-old woman with severe rheumatoid arthritis developed bullous lesions on the trunk, conjunctiva, and oral mucosa during treatment with tiobutarit, a new antirheumatic drug analogus to D-penicillamine. Histology showed a subepidermal blister, and circulating antibodies to the basement membrane zone were detected. The bullous lesions improved rapidly after discontinuation of tiobutarit. However, 3 years later, she was re-exposed to tiobutarit and the bullous lesions recurred within a week. This is the first confirmed case of tiobutarit-induced BP.

Anti-Inflammatory Agents↗

PubMed1989

Antigenic variation among Sendai virus strains detected by monoclonal antibodies.

Thirteen strains of Sendai virus isolated from various sources in the 1950's and after 1976 were compared for their reactivities with monoclonal antibodies prepared against the prototype strain MN of Sendai virus. Results revealed that while the 5 strains isolated in the 1950's reacted with all the monoclonal antibodies as the prototype strain did, the 2 strains isolated in 1976 and 1978 did not react with an F-specific monoclonal antibody, and the other 6 strains isolated after 1978 lacked reactivity with an HN-specific monoclonal antibody.

Antibodies, Monoclonal↗